Valve with internal member

ABSTRACT

A valve with an internal member is disclosed which allows exhaled carbon dioxide to escape from a breathing circuit when the circuit gas pressure drops below a threshold pressure. The valve operates by occluding one or more ports under a relatively high pressure and opening the one or more ports under a relatively low pressure. The internal member is attached to the body of the valve at two or more locations on the internal member. The internal member moves in a direction perpendicular to the gas flow through the valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 16/245,118, which has a 371(c) date of Jan. 10, 2019, which is acontinuation application of U.S. application Ser. No. 15/022,500, whichhas a 371(c) date of Mar. 16, 2016, which is a national stageapplication of International Patent Application No. PCT/NZ2014/000203,filed on Sep. 17, 2014, which claims the benefit of U.S. ProvisionalApplication No. 61/879,012, filed on Sep. 17, 2013 and U.S. ProvisionalApplication No. 61/912,390 filed on Dec. 5, 2013, the entireties of eachof which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure generally relates to positive airway pressuretherapy. More particularly, the present disclosure relates to valves(e.g., anti-asphyxia valves, constant flow valves) for use in positiveairway pressure therapy.

Description of the Related Art

Respiratory disorders deal with the inability of a sufferer to effect asufficient exchange of gases with the environment, leading to animbalance of gases in the sufferer. These disorders can arise as apathological consequence of an obstruction of the airway, insufficiencyof the lungs in generating negative pressure, an irregularity in thenervous function of the brain stem, or some other disorder. Treatment ofsuch disorders is diverse and depends on the particular respiratorydisorder being targeted. In the first instance, a constriction of theairway, otherwise known as an obstructive apnea or a hypopnea(collectively referred to as obstructive sleep apnea or OSA), can occurwhen the muscles that normally keep the airway open in a patient relaxduring slumber to the extent that the airway is constrained orcompletely closed off, a phenomenon often manifesting itself in the formof snoring. When this occurs for a significant period of time, thepatient's brain typically recognizes the threat of hypoxia and partiallywakes the patient in order to open the airway so that normal breathingmay resume. The patient may be unaware of these occurrences, which mayoccur as many as several hundred times per session of sleep. Thispartial awakening may significantly reduce the quality of the patient'ssleep, over time potentially leading to a variety of symptoms, includingchronic fatigue, elevated heart rate, elevated blood pressure, weightgain, headaches, irritability, depression, and anxiety.

Obstructive sleep apnea is commonly treated with the application ofcontinuous positive airway pressure (CPAP) therapy. Continuous positiveairway pressure therapy involves delivering a flow of gas to a patientat a therapeutic pressure above atmospheric pressure that will reducethe frequency and/or duration of apneas and/or hypopneas. This therapyis typically delivered by using a continuous positive airway pressuredevice (CPAP device) to propel a pressurized stream of air through aconduit to a patient through an interface or mask located on the face ofthe patient. The stream of air may be heated to near-body temperature.In some configurations, the stream of air may be humidified. In somesuch configurations, the stream of air may be humidified by forcing thestream of air to travel through a humidification chamber containingwater and a heater for heating the water. In such configurations, theheater encourages the evaporation of the water, which in turn partiallyor fully saturates the stream of air with moisture. This moisture mayhelp to ameliorate discomfort and/or mucosal tissue damage that mayarise from the use of unhumidified CPAP therapy.

During exhalation, the patient's exhaled gases typically flow out ofbias flow holes located on the interface, on the connection between theinterface and the conduit, or elsewhere in the CPAP circuit (where‘circuit’ here is defined as the passageway extending from the inlet ofthe blower to the interface outlet on or within the interface). Suchholes are typically made relatively small to reduce noise, and in usethe exhaled gases are pushed through the ports or holes by the gasesincoming at therapeutic pressure at rates sufficient to keep CO2rebreathing at acceptable levels. However, under relatively low pressureconditions, for example, when the patient is not receiving therapy,gases exhaled by the patient may not be able escape from such holes atsuch rates, and additionally a larger volume of exhaled gases may becomeentrained in the CPAP circuit on the way out to the flowgenerator/blower inlet. The combination of these two problems mayelevate CO2 rebreathing by the patient to unacceptable or undesirablelevels.

SUMMARY OF THE INVENTION

In the present disclosure, valves are provided that can be placed in theCPAP circuit that comprises ports open to the environment, where thevalve has some means of closing the ports under relatively high pressureconditions (i.e., therapeutic CPAP conditions) and some means of openingthe ports under relatively low pressure conditions. In someapplications, such valves may be called anti-asphyxia valves (AAvalves). In some preferred configurations, such valves are placed closeto the patient, e.g. in, at, or close to the interface.

In some configurations, such a valve comprises one or more relativelylarge ports open to the environment and a flap cantilevered to aninternal wall of the valve at one end, where the flap is biased towardsa neutral position. Under relatively high pressure conditions, the flapflexes in the direction of the flow and over the ports, and underrelatively low pressure conditions, the valve remains in a neutralposition (or may flex away from the patient due to exhaled gases flow).In this way, under low pressure conditions, exhaled gases may escapethrough the ports and the risk of unacceptable CO2 rebreathing may dropto acceptable levels, while under high pressure conditions a low levelof leak is maintained and exhaled gases can escape through the bias flowholes.

There are certain disadvantages to such flap-type valves. In thesevalves, during the transition from a relatively low pressure to arelatively high pressure, the flap quickly ‘slaps’ or moves over thevalve ports in such a way that creates a pressure ‘spike’ or quickchange in pressure in the CPAP circuit, and this ‘spike’ creates audiblenoise. Additionally, in such a valve, the flap and the ports aredisposed adjacent to each other along the length of the valve, which canmake the valve relatively long. In use, a relatively long valve attachedto, for example, an interface, may press against a patient's mattress orpillow and displace the mask away from the face, which may disrupt thesealing of the mask. Finally, the traditional port(s) on such a valveis/are relatively large, and exhaled flow through the port(s) maygenerate a relatively high level of noise due to port size. Accordingly,it is an object of the invention to present a solution or ameliorate atleast one or more of the above problems, or at least provide the publicwith a useful choice.

The present disclosure also describes valves that can be used asconstant flow valves, which are valves that can be used to maintain aconstant gas flow rate through a gas conduit under varying pressureconditions. The constant flow valve can progressively close the ports asthe flow rate decreases, such that the valve allows relatively moregases to escape to the environment at a higher flow rate and relativelyless gases to escape at a lower flow rate. In this way, the flow rate ofthe gases reaching the mask can be maintained at a generally constantflow rate.

Thus, in accordance with at least one of the embodiments disclosedherein, a valve can comprise a body with an interior surface defining apassageway. One or more ports can extend through the body to providefluid communication between the passageway and the environment. At leastone internal member can be attached to the body at two or morediscontinuous attachment positions on the internal member, the internalmember having a closed configuration that occludes the one or more portswhen a gas pressure in the valve is above a threshold pressure and anopen configuration that allows gas to pass from the passageway to theenvironment when the gas pressure in the valve is at or below athreshold pressure.

In some configurations, the interior surface can be curved.

In some configurations, the at least one internal member can move in adirection that is substantially perpendicular to the direction of gasesflow through the valve. The at least one internal member can beconfigured to progressively roll over the interior surface of the body.The at least one internal member can transition between the openconfiguration and the closed configuration at a distinct thresholdpressure.

The at least one internal member can transition between the openconfiguration and the closed configuration during a range of pressures.In some configurations, the range of pressures is at least approximately2 cm H2O and/or less than or equal to approximately 3 cm H2O. In someconfigurations, the range of pressures is at least approximately 1.5 cmH2O and/or less than or equal to approximately 4 cm H2O.

The one or more ports can be located at generally the same positionalong the length of the valve as the at least one internal member.

In some configurations, the body can be a round or oval tube and the atleast one internal member can extend around at least part of an innercircumference of the body in the closed configuration.

The one or more ports can be disposed around part of the circumferenceof the body. In some configurations, the one or more ports can bedisposed around the entire circumference of the body. The one or moreports can be circular holes having a diameter of approximately 1 mm. Insome configurations, the one or more ports have a combined venting areaof at least approximately 30 mm² and/or less than or equal toapproximately 600 mm². In some configurations, the one or more portshave a combined venting area of approximately 40 mm2.

In some configurations, the threshold pressure can be approximately 2 cmH2O.

The length of the at least one internal member between attachmentpositions can be approximately the same as the length of the interiorsurface of the body between the attachment positions. In someconfigurations, the at least one internal member is a continuous memberconfigured to extend around the interior surface of the body in theclosed configuration.

The valve can be configured to be placed at an inlet of a patientinterface. In some configurations, the valve can be configured to beplaced in-line between a patient interface and a blower.

The at least one internal member can be attached to the body by poststhat extend through the body. In some configurations, the at least oneinternal member can be attached to the body by an adhesive. In someconfigurations, the at least one internal member is attached byovermoulding onto the body.

In some configurations, the valve can be an anti-asphyxia valve. Inother configurations, the valve can be a constant flow valve. The atleast one internal member can transition between the open configurationand the closed configuration during pressures ranging from at leastapproximately 0 cm H2O and/or less than or equal to approximately 20 cmH2O.

In accordance with at least one of the embodiments disclosed herein, avalve can comprise a body with an interior surface defining apassageway, the body configured to be positioned in-line with a flow ofrespiratory gases. One or more ports can extend through the body toprovide fluid communication between the passageway and the environment,the one or more ports disposed around at least part of a circumferenceof the body. At least one internal member can be attached to the body attwo or more discontinuous attachment positions on the internal member,the attachment positions being generally at the same location along thelength of the valve as the one or more ports. The at least one internalmember can be in an open configuration that allows gas to pass from thepassageway to the environment when the gas pressure in the valve is ator below a threshold pressure, the at least one internal member beingbiased radially inward away from the interior surface. Also, the atleast one internal member can be in a closed configuration that occludesthe one or more ports when a gas pressure in the valve is above athreshold pressure, the at least one internal member moving radiallyoutward toward the interior surface to occlude the one or more ports.

In some configurations, the interior surface can be curved. In someconfigurations, the body can be round.

In some configurations, the at least one internal member can move in adirection that is substantially perpendicular to the direction of gasesflow through the valve. The at least one internal member can beconfigured to progressively roll over the interior surface of the body.The at least one internal member can transition between the openconfiguration and the closed configuration at a distinct thresholdpressure.

The at least one internal member can transition between the openconfiguration and the closed configuration during a range of pressures.In some configurations, the range of pressures is at least approximately2 cm H2O and/or less than or equal to approximately 3 cm H2O. In someconfigurations, the range of pressures is at least approximately 1.5 cmH2O and/or less than or equal to approximately 4 cm H2O.

In some configurations, the one or more ports can be disposed around theentire circumference of the body. The one or more ports can be circularholes having a diameter of approximately 1 mm. In some configurations,the one or more ports have a combined venting area of at leastapproximately 30 mm² and/or less than or equal to approximately 600 mm².In some configurations, the one or more ports have a combined ventingarea of approximately 40 mm2.

In some configurations, the threshold pressure can be approximately 2 cmH2O.

The length of the at least one internal member between attachmentpositions can be approximately the same as the length of the interiorsurface of the body between the attachment positions. In someconfigurations, the at least one internal member is a continuous memberconfigured to extend around the interior surface of the body in theclosed configuration.

The valve can be configured to be placed at an inlet of a patientinterface. In some configurations, the valve can be configured to beplaced in-line between a patient interface and a blower.

The at least one internal member can be attached to the body by poststhat extend through the body. In some configurations, the at least oneinternal member can be attached to the body by an adhesive. In someconfigurations, the at least one internal member is attached byovermoulding onto the body.

In some configurations, the valve can be an anti-asphyxia valve. Inother configurations, the valve can be a constant flow valve. The atleast one internal member can transition between the open configurationand the closed configuration during pressures ranging from at leastapproximately 0 cm H2O and/or less than or equal to approximately 20 cmH2O.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments and modifications thereof will become apparent tothose skilled in the art from the detailed description herein havingreference to the figures that follow, of which:

FIG. 1 is a perspective view of an interface with an attached valve inaccordance with an embodiment of the present disclosure.

FIG. 2 is a top perspective view of a valve in accordance with anembodiment of the present disclosure.

FIG. 3 is close-up view of the valve of FIG. 2.

FIG. 4 is a top plan view of the valve of FIG. 2.

FIG. 5 is a top plan view of the valve of FIG. 2 in a partially closedconfiguration.

FIG. 6 is a top plan view of the valve of FIG. 2 in an almost fully orfully closed configuration.

FIG. 7 is a top perspective view of an internal member on an internalring support in accordance with an embodiment of the present disclosure.

FIG. 8 is a top plan view of a valve with the internal member of FIG. 7.

FIG. 9 is a cross-sectional view of the internal ring of FIG. 8.

FIG. 10 is a cross-sectional top plan view of an internal member on oneside of the valve in accordance with an embodiment of the presentdisclosure.

FIG. 11 is a cross-sectional top plan view of a valve with internalmembers on opposite sides of the valve in accordance with an embodimentof the present disclosure.

FIG. 12 is a cross-sectional top plan view of a valve with an internalmember having four folds in accordance with an embodiment of the presentdisclosure.

FIG. 13 is a cross-sectional top plan view of a valve with an internalmember having five folds in accordance with an embodiment of the presentdisclosure.

FIG. 14 is a cross-sectional top plan view of a valve with a squareshaped body and posts attached towards the middle of the walls inaccordance with an embodiment of the present disclosure.

FIG. 15 is a cross-sectional top plan view of the valve of FIG. 14, inthe closed configuration.

FIG. 16 is a cross-sectional top plan view of a valve with a squareshaped body and posts attached at the corners of the walls in accordancewith an embodiment of the present disclosure.

FIG. 17 is a cross-sectional top plan view of the valve of FIG. 16, inthe closed configuration.

FIG. 18 is a cross-sectional top plan view of a valve with an octagonalshaped body in accordance with an embodiment of the present disclosure.

FIG. 19 is a cross-sectional top plan view of the valve of FIG. 18, inthe closed configuration.

FIG. 20 is a cross-sectional top plan view of a valve with a hexagonalshaped body in accordance with an embodiment of the present disclosure.

FIG. 21 is a cross-sectional top plan view of the valve of FIG. 20, inthe closed configuration.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In the present disclosure, valves are provided that can be placedin-line in the CPAP circuit with ports that are open to the environment,where the valve can close the ports under relatively high pressureconditions and open the ports under relatively low pressure conditions.In some configurations, these types of valves are known as anti-asphyxiavales (AA valves). In some configurations, the valves are placed closeto the patient, e.g. in, at, or close to the interface.

In some configurations, the valve comprises one or more relatively largeports open to the environment and a flap cantilevered at one end to aninternal wall of the valve, where the flap is biased towards a neutralposition. Under relatively high pressure conditions, the flap can flexin the direction of the gases flow and occlude the ports. Underrelatively low pressure conditions, the valve can remain in a neutralposition (or may flex away from the patient due to exhaled gases flow).Under low pressure conditions, exhaled gases can escape through theports and the risk of unacceptable CO2 rebreathing may be mitigated toacceptable levels, while under high pressure conditions the venting ofexhaled gases is maintained through the bias flow holes.

The present disclosure also describes valves that can be used asconstant flow valves, which are valves that can be used to maintain aconstant gas flow rate through a gas conduit under varying pressureconditions. For example, as described in further detail below, theconstant flow valve can progressively close the ports as the flow ratedecreases, such that the valve allows relatively more gases to escape tothe environment at a higher flow rate and relatively less gases toescape at a lower flow rate. In this way, the flow rate of the gasesreaching the mask can be maintained at a generally constant flow rate.

Some non-limiting configurations of valves 100 are illustrated in FIGS.1-4. FIG. 1 illustrates a valve 100 attached to the elbow connector 52of a full face mask 50. However, in some embodiments, the valve 100 canbe used with any type of patient interface, such as pillow masks, oralmasks, oral-nasal masks, nasal masks, nasal cannulae, etc. In theillustrated configuration, the valve 100 is disposed in-line with thegases conduit 60, such that the valve 100 has a first end that is influid communication with the mask 50 and a second end that is in fluidcommunication with the gases conduit 60. The valve can be placedanywhere in the gas circuit between the blower inlet and the interfaceinlet. However, the valve 100 is preferably attached at or near theinlet of a patient interface.

Positioning the valve closer to the interface inlet beneficially reducesthe amount of dead space where CO₂ gases can accumulate and beneficiallyreduces the rebreathing of exhaled gases by the patient. For example, ifthe valve is positioned near the blower, then CO2 gases would be able toaccumulate in at least the mask, elbow connector and the conduit beforeit can exit to the environment through the valve. The amount of CO2rebreathing may be at unacceptable levels in this situation. Bypositioning the valve adjacent the elbow connector, CO2 gases would onlyaccumulate in the mask and elbow connector, reducing the amount of CO2rebreathing to acceptable levels.

With reference to FIG. 2, the valve 100 can have a tubular body 101 withan interior surface 102 and an exterior surface 103. The interiorsurface 102 surrounds a passageway 118 through which fluids can flow. Inthe illustrated configuration, the valve 100 has a cylindrical shapewith a generally circular cross-section. The valve can have any of aplurality of different shapes, such as a tube with an oval, square,rectangular or polygonal cross-section. The internal diameter of thevalve can be any size that is suitable for use in a respiratory circuit,preferably without restricting the gas flow. For example, the internaldiameter of the body 101 can be approximately 20 mm. In someconfigurations, the internal diameter of the body can range from atleast approximately 15 mm and/or less than or equal to approximately 25mm.

In some configurations, the body of the valve may not be straight andinstead may have a bend, such as a 45 degree or 90 degree bend. The bendin the body of the valve can advantageously help route the circuit tominimize interference with other objects, such as the patient's mattressor pillow, which can lead to displacement of the mask away from the faceand disruption of the mask seal. In some configurations, the valve canbe integrated or built into the elbow connector. This can position thevalve closer to the interface inlet, beneficially reducing the amount ofdead space, as discussed above.

The valve 100 has an internal member 104 that can be coupled to theinterior wall 102 of the valve 100, as illustrated in FIGS. 2-4. Theinternal member can be configured to occlude the ports of the valve whenthe gas flow pressure is above a threshold pressure and not occlude theports when the gas flow pressure is below the threshold pressure, asdescribed in further detail below. In the illustrated configuration, theinternal member 104 is an elongate ribbon in the passageway 118 that isapposed to the ports of the valve 100. The illustrated internal member104 is a continuous ribbon that is attached to the body 101 by threeposts 106 that extend through the body 101 of the valve 100.

With continued reference to FIG. 2, the valve 100 comprises one or moreports 110. The ports 110 can be through holes in the body 101 of thevalve 100 that extend from the interior surface 102 to the exteriorsurface 103 such that the passageway 118 is in fluid communication withthe environment through the ports 110. In the illustrated configuration,the valve 100 has a plurality of relatively small ports 110 that arearranged in two rows extending around the body 101. The ports 110 arelocated at approximately the same position along the length of the valve100 as the internal member 104, such that the internal member 104 canoverlap and occlude the ports 110 when the gas flow pressure is above athreshold pressure.

When the gas flow pressure is below a certain threshold, the internalmember 104 is in its neutral configuration and curves away from theinterior surface 102, forming folds 108 in the internal member 104. Thefolds 108 are approximately the same length as the sealing surface 112,which is the area on the interior wall 102 between the posts 106 wherethe ports 110 are disposed. When the gas flow pressure is above acertain threshold, the folds 108 are urged to curve toward the interiorsurface 102 until the folds 108 of the internal member 104 abut thesealing surface 112 and occlude the ports 110.

In use, under relatively low pressure conditions, exhaled gases canescape through ports 110 when the internal member 104 is in a neutralposition as shown in FIG. 4. In the neutral position, the internalmember 104 does not occlude the ports 110 and exhaled gases can flowfreely through the ports 110 to the environment. When the systemtransitions to relatively high pressure conditions (e.g. the CPAP bloweris turned on) and the pressure of the gas flow meets or exceeds athreshold pressure, the leading contact edges 120 of the folds 108 ofthe internal member 104 can roll to abut the sealing surface 112 of thevalve 100, thereby occluding the ports 110 as shown in FIG. 5. In someconfigurations, the pressure of the gases moving through the valve 100can apply forces on the folds 108 of the internal member 104 to move thefolds 108 against the interior surface 102 of the valve 100 in adirection substantially perpendicular to the direction of gas flow. Inthese configurations, the folds 108 are moved substantially by the gaspressure within the valve 100 and not by the forces from the gasvelocity, and the valve 100 can be described as a pressure-dependentvalve rather than a flow-dependent valve.

The internal member is preferably configured to be flexible. Theinternal member can be made of a pliable material that can bend and flexeasily, such as for example silicone. The internal member can also havea shape that is configured for flexibility, such as for example a thin,flat shape. The thickness of an internal member for an AA valve can beat least approximately 0.3 millimeter and/or less than or equal toapproximately 0.4 millimeter. This internal member may have an operatingthreshold pressure of approximately 2-3 cm H2O. In some configurations,the thickness of the internal member can be at least approximately 0.1millimeter and/or less than or equal to approximately 0.5 millimeter.

The valves described herein advantageously operate without significantlyrestricting the flow path. As mentioned above, the internal member 104moves in a direction substantially perpendicular to the direction of gasflow and only a thin edge, or cross-section, of the internal member 104is in the path of the gas flow, as can be seen in FIG. 4. In contrast,other valve designs, such as the flap type valve, can restrict the flowpath. For example, a flap valve in certain positions may almostcompletely block the flow path and the air flow is forced to go aroundthe flap valve or push the flap out of the way. This can affect the flowmeasurements of the respiratory device (e.g., CPAP). The valvesdisclosed herein advantageously are not flow dependent, rather pressuredependent, and can even operate when there is no change in flow velocityor even zero flow velocity.

In some configurations, the rolling motion of the internal member 104and the progressive occlusion of the ports 110 can advantageously helpto reduce valve noises, which are traditionally caused by the slappingmotion of a traditional flap valve. When the internal member 104 isexposed to gas flow that meets or exceeds the threshold pressure, thefolds 108 of the internal member 104 can gradually roll over the sealingsurface 112 until the sealing surface 112 and the ports 110 aresubstantially covered by the folds 108 and the valve 100 issubstantially in a closed configuration, as shown in FIG. 6. FIGS. 4-6taken together may represent a continuum of internal member 104positions from substantially open to substantially closed. In someconfigurations, the pressure at which the valve 100 may close from anopen state, or open from a closed state, is approximately 2 cm H2O. Insome configurations, the pressure at which the valve transitions fromthe open and closed states can be at least approximately 2 cm H2O and/orless than or equal to approximately 3 cm H2O. In some configurations,the pressure at which the valve transitions from the open and closedstates can be at least approximately 1.5 cm H2O and/or less than orequal to approximately 4 cm H2O.

In some configurations, the internal member 104 can progressively abutthe sealing surface 112 through a range of operating pressures. Forexample, the internal member 104 can be in a fully open configuration,as illustrated in FIG. 4, until the gas pressure increases to reachapproximately a lower threshold pressure, such as 1.5 cm H2O. The folds108 can gradually roll to abut an increasing area of the sealing surface112 as the pressure continues to increase. An increasing number of ports110 are also progressively occluded as the folds 108 gradually rollagainst the sealing surface 112. Thus, as the gas pressure increases,the total area of the ports 110 through which exhaled gases can escapedecreases. When the gas pressure reaches approximately an upperthreshold pressure, such as 4 cm H2O, the folds 108 can be substantiallyabutted against the sealing surface 112 in a fully closed configuration.

Similarly, as the gas pressure decreases, the internal member 104 canstart to gradually roll away from the sealing surface when the gaspressure reaches approximately an upper threshold pressure. The internalmember 104 can progressively roll away from the sealing surface 112 asthe gas pressure continues to decrease. An increasing number of ports110 are also progressively opened as the folds 108 gradually roll awayfrom the sealing surface 112, and the total area of the ports 110increases. When the gas pressure reaches approximately a lower thresholdpressure, the folds 108 are substantially separated from the sealingsurface, as illustrated in FIG. 4, and the internal member 104 is in afully open configuration. In some configurations, the lower thresholdpressure can be at least approximately 1.5 cm H2O and/or less than orequal to approximately 2.5 cm H2O. In some configurations, the upperthreshold pressure can be at least approximately 3 cm H2O and/or lessthan or equal to approximately 4 cm H2O.

The range of operating pressures of the internal member 104 whiletransitioning from an open to a closed configuration can be the same asthe range of pressures for transitioning from a closed to an openconfiguration. For example, the internal member 104 can start to rollonto the sealing surface 112 into a closed configuration atapproximately 1.5 cm H2O and be in a fully closed configuration atapproximately 4 cm H2O. The same internal member 104 can start to rollaway from the sealing surface 112 into an open configuration atapproximately 4 cm H2O and be in a fully open configuration atapproximately 1.5 cm H2O.

In some configurations, the range of operating pressures can bedifferent depending on whether the internal member 104 is transitioningfrom an open to closed configuration, or from a closed to openconfiguration. For example, the internal member 104 can start to rollonto the sealing surface 112 into a closed configuration atapproximately 2 cm H2O and be in a fully closed configuration atapproximately 4 cm H2O. The same internal member 104 can start to rollaway from the sealing surface 112 into an open configuration atapproximately 3 cm H2O and be in a fully open configuration atapproximately 1.5 cm H2O.

In some configurations, the internal member 104 can transition from theopen configuration to the closed configuration at a particular thresholdpressure, instead of gradually transitioning throughout a range ofoperating pressures. The valve can act as a “digital valve” where theinternal member is in an open configuration when the gas pressure is ator below a threshold value, and in a closed configuration when the gaspressure is above the threshold value. For example, the internal membercan be in the fully open configuration until the gas pressure reachesthe threshold value, such as 2 cm H2O. When the threshold value isreached, the internal member can transition to the fully closedconfiguration.

In some configurations, the valve can be a constant flow valve thathelps maintain a generally constant gas flow rate through a gas conduitunder varying pressure conditions. As described above, the internalmember can progressively roll over the ports through a range ofpressures. In constant flow valves, the internal member canprogressively occlude the ports as the flow rate decreases, which causesthe pressure to increase. The valve allows relatively more gases toescape to the environment through the ports at a higher flow rate andrelatively less gases to escape at a lower flow rate such that agenerally constant flow rate, or at least a small range of flow rates,is delivered to the mask. Preferably, the internal member is thickercompared to the internal member used for some other valves, such as theAA valve. For example, the thickness of the internal member for aconstant flow valve can be approximately 0.7 millimeter. In someconfigurations, the thickness of the internal member for a constant flowvalve can range from at least approximately 0.5 millimeter and/or lessthan or equal to approximately 1.0 millimeter. In some configurations,the internal member can start to roll onto the sealing surface into aclosed configuration at approximately 0 cm H2O and be in a fully closedconfiguration at approximately 20 cm H2O.

In a constant flow valve the internal member can progressively abut thesealing surface through a range of operating flow rates, which inverselycorresponds to a range of operating pressures. For example, the internalmember can be in a fully open configuration at a relatively high gasflow rate until the gas flow rate decreases to reach approximately anupper threshold flow rate. The upper threshold flow rate can have acorresponding gas pressure, such 0 cm H2O. The folds of the internalmember can gradually roll to abut an increasing area of the sealingsurface as the flow rate decreases, and consequently causes the pressureto increase. An increasing number of ports are also progressivelyoccluded as the folds gradually roll against the sealing surface. Thus,as the flow rate decreases and the gas pressure increases, the totalarea of the ports through which gases flowing through the valve canescape to environment decreases, allowing more gases to reach the mask.When the flow rate reaches approximately a lower threshold flow rate,the folds can be substantially abutted against the sealing surface in afully closed configuration such that substantially all the gases flowingthrough the constant flow rate valve are delivered to the mask. Thelower threshold flow rate can have a corresponding gas pressure, such as20 cm H2O.

Similarly, as the flow rate increases and the gas pressure decreases,the internal member can start to gradually roll away from the sealingsurface at approximately a lower threshold flow rate. The lowerthreshold flow rate can have a corresponding gas pressure, such 20 cmH2O. The internal member can progressively roll away from the sealingsurface as flow rate increases and consequently the gas pressuredecreases. An increasing number of ports are also progressively openedas the folds gradually roll away from the sealing surface and the totalarea of the ports through which gases can escape to the environmentincreases. When the flow rate reaches approximately an upper thresholdflow rate, the folds are substantially separated from the sealingsurface and the internal member is in a fully open configuration, suchthat gases are allowed to escape through all the ports of the valve. Theupper threshold flow rate can have a corresponding gas pressure, such as0 cm H2O.

The illustrated internal member 104 has generally an elongate,rectangular shape. In some configurations, the internal member 104 canhave other shapes, such as for example round shapes or zig-zag shapes.The internal member can be made of a pliable material that can bend andflex easily from the open configuration to the closed configuration. Forexample, the internal member can at least partially be made of silicone,rubber, flexible plastics, paper, etc.

In some configurations, as illustrated in FIGS. 2 and 3, the ports 108are located at approximately the same position along the length of thevalve 100 as the internal member 104, such that the internal member 104can overlap and occlude the ports 110 when the gas flow pressure isabove a threshold pressure. These configurations advantageously providefor a valve 100 that is compact and shorter in length than traditionalvalves, where the ports and valve flaps are sequentially next to eachother along the length of the valve.

In some configurations, as illustrated in FIGS. 2-4, the internal member104 is attached to the valve 100 by posts 106 that extend through thebody 101 of the valve 100. The posts 106 can be made of the samematerial as the internal member 104. In some configurations, the posts106 and internal member 104 can be made from different materials. Forexample, the posts 106 may be made of a plastic material while theinternal member 104 is made of rubber. The two components can be welded,adhered or otherwise coupled together. In some configurations, duringassembly the posts 106 can be forced through orifices that extendthrough the valve body 101. The orifices can be similarly-sized to theposts for a close fit between the orifices and posts. The posts 106 canhave flanges 107 that are wider than the orifices to hold the posts inplace and to help prevent the posts from being pulled back through theorifices, as illustrated in FIG. 4.

The internal member 104 can be coupled to the body 101 by any of aplurality of different types of functional couplers. For example, theinternal member 104 can be glued to the interior surface 102 of thevalve 100 using an adhesive, overmoulded onto the body 101 of the valve100, or affixed to the interior surface 102 of the valve 100 viaultrasonic welding. Any suitable attachment method can be used andpreferably the internal member 104 is pliable enough to cover the ports110, in use.

In some configurations, the internal member 104 can be removable fromthe valve body 101 for easy replacement, cleaning or service. Forexample, the posts 106 can be deformable so that they can be detachedfrom the body 101 and preferably re-attachable after cleaning orservicing. A removable internal member can advantageously allow forcustomization of the valve performance, such as customizing the gaspressure at which the internal member switches from the open to closedconfiguration.

In some configurations, the internal member 104 can be attached to aninternal ring 114 or other element that may be inserted inside thepassageway 118 of the valve 100, instead of or in addition to beingattached or anchored directly to the body 101 of the valve 100, asillustrated in FIGS. 7-8. With reference to FIGS. 7 and 9, the internalring 114 can have gaps 116 through which gases can flow through to theports 110. The internal ring 114 can be pressed into the body 101 of thevalve 100, such as through an interference fit, or can be coupled by anyretaining feature, such as for example hooks, clips, screw threads,tongue-and-grooves, etc. The internal ring 114 can be removable from thebody 101 of the valve 100, and in some configurations, the internalmember 104 can be removable from the internal ring 114.

The ports 110 are through holes in the body 101 of the valve 100 thatenable fluid communication between the passageway 118 and theenvironment. The ports 110 can be any suitable size, shape, and/orconfiguration. In the illustrated configurations, the ports are smallcircular holes that are generally perpendicular to the body 101, suchthat the ports extend normal to the interior and exterior surfaces. Inother configurations, the ports can extend at an angle to the body 101.The port directions can allow for directing the flow of gases ventedfrom the valve. In some configurations, the ports can have an ovalshape, rectangular shape, or other shape besides circular holes. Forexample, the ports can comprise an elongate oval shaped hole disposedbetween the posts. In some configurations, the ports can include acombination of different shaped holes, such as polygonal ports and ovalports. The ports are preferably relatively small holes, which can helpreduce noises from the venting gases. In some configurations, the portsare substantially circular holes of approximately 1 mm in diameter. Insome configurations, the ports can range from at least approximately 0.5mm in diameter and/or less than or equal to approximately 3 mm indiameter.

The total venting area of the ports is configured to allow adequate CO2flushing while keeping the ports small to reduce venting noises. Forexample, the total cross-sectional area of all the ports can beapproximately 40 mm². This can be achieved, for example, withapproximately 50 ports, each having a 1 mm diameter hole. In someconfigurations, the total cross-sectional area of all the ports canrange from at least approximately 30 mm² and/or less than or equal toapproximately 600 mm².

With reference to FIGS. 1-3 and as described above, the illustratedembodiment comprises a plurality of ports that are arranged in two rowsextending around the body 101. In some configurations, the ports maycomprise a plurality of holes arranged in a single row or more than tworows extending around the body, or partially around the body. The ports110 are located at approximately the same position along the length ofthe valve 100 as the internal member 104, such that the internal member104 can overlap and occlude the ports 110 when the gas flow pressure isabove a threshold pressure. In some configurations, the ports may onlybe disposed around a portion or portions of the body. For example, theports may be disposed on half of the circumference of the body, asillustrated in FIG. 10. In another example, the ports may be disposed ontwo opposite portions of the body.

In some preferred configurations, the size of the ports 110 is selectedin such a way that both acceptable CO2 flushing and acceptable noisegeneration are achieved. In some preferred configuration, the valveports 110 and the internal member 104 are coaxial along the length ofthe valve 100, which may be an efficient use of space.

The length of the folds 108 of the internal member 104 can beapproximately the same length as the corresponding sealing surface 112,such that the internal member 104 adequately occludes all the ports 110when the internal member 104 is in the closed configuration. In someconfigurations, the folds 108 can be slightly shorter or slightly largerin length than the sealing surface 112 and still provide sufficientocclusion of the ports 110. The internal member 104 can be made of apliable material, such as rubber, that can stretch and/or compress toconform to the length of the sealing surface 112. For example, in avalve having an internal diameter of about 20 mm, the length of theinternal member extending around the entire interior surface can beapproximately 61 mm.

In the embodiments illustrated in FIGS. 2-6, the internal member 104 isa single continuous member connected integrally with the posts 106.However, in other embodiments, the internal member 104 can be severaldiscontinuous internal members, each attached to the body 101 at bothends of the internal member, such as illustrated in FIGS. 10-11. FIG. 10illustrates a cross-sectional view of a valve 100 with an internalmember 104 that comprises a single fold 108 and is attached to theinterior surface 102 at both ends of the internal member 104. The valve100 comprises a set of ports 110 on one side of the valve 100. FIG. 11illustrates a configuration of a valve 100 comprising two internalmembers 104, each comprising a fold 108. Each internal member 104 isattached to the interior surface 102 at both ends of the internalmembers 104.

The internal member 104 can have any number of folds 108. For example,the internal member 104 can comprise one, two, three or more than threefolds 108 along the length of the internal member 104. Some non-limitingexamples of these configurations are shown in FIGS. 12-13. FIG. 12illustrates a configuration of a valve 100 in which the internal member104 comprises four folds 108 and the valve 100 comprises four sets ofports 110. FIG. 13 shows a configuration in which the internal member104 comprises five folds 108 and the valve 100 comprises five sets ofports 110. As implied in FIGS. 10-13, the valve can comprise any numberof folds and a corresponding number of sets of ports. However, in someembodiments, the number of folds and the number of sets of port may notbe the same.

The valve body can have any of a plurality of different shapes, inaddition to the circular or round shapes described above. In someconfigurations, the valve body can be a tube with a squarecross-sectional shape, as illustrated in FIGS. 14-17. The valve body canbe a tube having an octagonal cross-sectional shape, as illustrated inFIGS. 18-19, or a hexagonal cross-sectional shape, as illustrated inFIGS. 20-21. In some configurations, the valve body can be a tube withother cross-sectional shapes besides those provided in the examples ofFIGS. 14-21, such as rectangular, oval, triangular, other polygonalshapes, or any other shape.

FIG. 14 illustrates a cross-sectional view of a valve 200 having asquare shaped body. The internal member 204 is attached to the body withposts 206 located toward the middle of the side walls. The illustratedconfiguration has four posts 206 and one internal member 204. However,as discussed above in other configurations, the valve can have more thanone internal member and can be attached at any number of differentlocations on the body in more or less than four post locations. Theillustrated internal member 204 has four folds 208 that are configuredto occlude ports 210 that are located toward the corners of the walls.FIG. 15 illustrates the valve 200 in a closed configuration. The folds208 can extend around the corners of the walls to occlude the ports 210.

FIG. 16 illustrates a cross-sectional view of a valve 300 having asquare shaped body, similar to FIG. 14, but with the posts 306 attachedat the corners of the body. In the open configuration, the folds 308 arebiased away from the walls of the body so that the ports 310 are open tothe environment. In the closed configuration, as illustrated in FIG. 17,the folds 308 are against the walls of the body to occlude the ports310. Preferably the internal member 304 is compliant so that it cancompress to a shorter length in the closed configuration and extend to alonger length in the open configuration.

FIG. 18 illustrates a cross-sectional view of a valve 400 having anoctagonal shaped body. The internal member 404 is attached to the bodywith posts 406 located at four of the corners of the side walls. Theillustrated configuration has four posts 406 and one internal member404. However, as discussed above in other configurations, the valve canhave more than one internal member and can be attached at any number ofdifferent locations on the body in more or less than four postlocations. The illustrated internal member 404 has four folds 408 thatare configured to occlude ports 410 that are located toward the cornersof the walls. FIG. 19 illustrates the valve 400 in a closedconfiguration. The folds 408 can extend around the corners of the wallsto occlude the ports 410.

FIG. 20 illustrates a cross-sectional view of a valve 500 having ahexagonal shaped body. The internal member 504 is attached to the bodywith posts 506 located toward the middle of some of the side walls. Theillustrated configuration has three posts 506 and one internal member204. However, as discussed above in other configurations, the valve canhave more than one internal member and can be attached at any number ofdifferent locations on the body in more or less than three postlocations. The illustrated internal member 504 has three folds 508 thatare configured to occlude ports 510 that are located on the walls of thebody. FIG. 21 illustrates the valve 500 in a closed configuration. Thefolds 508 can extend around the corners of the walls to occlude theports 510. In the illustrated configuration, each fold 508 lies againstthree of the walls, partially over two walls and one entire wall.

Preferred Features:

1. A valve comprising:

a body with an interior surface defining a passageway;

one or more ports through the body to provide fluid communicationbetween the passageway and the environment; and

at least one internal member attached to the body at two or morediscontinuous attachment positions on the internal member, the internalmember having a closed configuration that occludes the one or more portswhen a gas pressure in the valve is above a threshold pressure and anopen configuration that allows gas to pass from the passageway to theenvironment when the gas pressure in the valve is at or below athreshold pressure.

2. The valve of paragraph 1, wherein the interior surface is curved.

3. The valve of paragraph 1 or paragraph 2, wherein the at least oneinternal member moves in a direction that is substantially perpendicularto the direction of gases flow through the valve.

4. The valve of any one of the preceding paragraphs, wherein the atleast one internal member is configured to progressively roll over theinterior surface of the body.

5. The valve of any one of the preceding paragraphs, wherein the atleast one internal member transitions between the open configuration andthe closed configuration at a distinct threshold pressure.

6. The valve of any one of the paragraphs 1-4, wherein the at least oneinternal member transitions between the open configuration and theclosed configuration during a range of pressures.

7. The valve of paragraph 6, wherein the range of pressures is at leastapproximately 2 cm H2O and/or less than or equal to approximately 3 cmH2O.

8. The valve of paragraph 6, wherein the range of pressures is at leastapproximately 1.5 cm H2O and/or less than or equal to approximately 4 cmH2O.

9. The valve of any one of the preceding paragraphs, wherein the one ormore ports is located at generally the same position along the length ofthe valve as the at least one internal member.

10. The valve of any one of the preceding paragraphs, wherein the bodyis a round or oval tube and the at least one internal member extendsaround at least part of an inner circumference of the body in the closedconfiguration.

11. The valve of paragraph 10, wherein the one or more ports aredisposed around part of the circumference of the body.

12. The valve of paragraph 10, wherein the one or more ports aredisposed around the entire circumference of the body.

13. The valve of any one of the preceding paragraphs, wherein the one ormore ports are circular holes having a diameter of approximately 1 mm.

14. The valve of any one of the preceding paragraphs, wherein the one ormore ports have a combined venting area of at least approximately 30 mm²and/or less than or equal to approximately 600 mm².

15. The valve of any one of the preceding paragraphs, wherein the one ormore ports have a combined venting area of approximately 40 mm².

16. The valve of any one of the preceding paragraphs, wherein thethreshold pressure is approximately 2 cm H2O.

17. The valve of any one of the preceding paragraphs, wherein a lengthof the at least one internal member between attachment positions isapproximately the same as a length of the interior surface of the bodybetween the attachment positions.

18. The valve of any one of the preceding paragraphs, wherein the atleast one internal member is a continuous member configured to extendaround the interior surface of the body in the closed configuration.

19. The valve of any one of the preceding paragraphs, wherein the valveis configured to be placed at an inlet of a patient interface.

20. The valve of any one of the preceding paragraphs, wherein the valveis configured to be placed in-line between a patient interface and ablower.

21. The valve of any one of the preceding paragraphs, wherein the atleast one internal member is attached to the body by posts that extendthrough the body.

22. The valve of any one of paragraphs 1-20, wherein the at least oneinternal member is attached to the body by an adhesive.

23. The valve of any one of paragraphs 1-20, wherein the at least oneinternal member is attached by overmoulding onto the body.

24. The valve of any one of the preceding paragraphs, wherein the valveis an anti-asphyxia valve.

25. The valve of any one of paragraphs 1-23, wherein the valve is aconstant flow valve.

26. The valve of paragraph 25, wherein the at least one internal membertransitions between the open configuration and the closed configurationduring pressures ranging from at least approximately 0 cm H2O and/orless than or equal to approximately 20 cm H2O.

27. A valve comprising:

a body with an interior surface defining a passageway, the bodyconfigured to be positioned in-line with a flow of respiratory gases;

one or more ports through the body to provide fluid communicationbetween the passageway and the environment, the one or more portsdisposed around at least part of a circumference of the body; and

at least one internal member attached to the body at two or morediscontinuous attachment positions on the internal member, theattachment positions being generally at the same location along thelength of the valve as the one or more ports;

wherein the at least one internal member is in an open configurationthat allows gas to pass from the passageway to the environment when thegas pressure in the valve is at or below a threshold pressure, the atleast one internal member being biased radially inward away from theinterior surface;

wherein the at least one internal member is in a closed configurationthat occludes the one or more ports when a gas pressure in the valve isabove a threshold pressure, the at least one internal member movingradially outward toward the interior surface to occlude the one or moreports.

28. The valve of paragraph 27, wherein the interior surface is curved.

29. The valve of paragraph 27 or paragraph 28, wherein the body isround.

30. The valve of any one of paragraphs 27-29, wherein the at least oneinternal member moves in a direction that is substantially perpendicularto the direction of gases flow through the valve.

31. The valve of any one of paragraphs 27-30, wherein the at least oneinternal member is configured to progressively roll over the interiorsurface of the body.

32. The valve of any one of paragraphs 27-31, wherein the at least oneinternal member transitions between the open configuration and theclosed configuration at a distinct threshold pressure.

33. The valve of any one of paragraphs 27-31, wherein the at least oneinternal member transitions between the open configuration and theclosed configuration during a range of pressures.

34. The valve of paragraph 33, wherein the range of pressures is atleast approximately 2 cm H2O and/or less than or equal to approximately3 cm H2O.

35. The valve of paragraph 33, wherein the range of pressures is atleast approximately 1.5 cm H2O and/or less than or equal toapproximately 4 cm H2O.

36. The valve of any one of paragraphs 27-35, wherein the one or moreports are disposed around the entire circumference of the body.

37. The valve of any one of paragraphs 27-36, wherein the one or moreports are circular holes having a diameter of approximately 1 mm.

38. The valve of any one of paragraphs 27-37, wherein the one or moreports have a combined venting area of at least approximately 30 mm²and/or less than or equal to approximately 600 mm².

39. The valve of any one of paragraphs 27-38, wherein the one or moreports have a combined venting area of approximately 40 mm².

40. The valve of any one of paragraphs 27-39, wherein the thresholdpressure is approximately 2 cm H2O.

41. The valve of any one of paragraphs 27-40, wherein a length of the atleast one internal member between attachment positions is approximatelythe same as a length of the interior surface of the body between theattachment positions.

42. The valve of any one of paragraphs 27-41, wherein the at least oneinternal member is a continuous member configured to extend around theinterior surface of the body in the closed configuration.

43. The valve of any one of paragraphs 27-42, wherein the valve isconfigured to be placed at an inlet of a patient interface.

44. The valve of any one of paragraphs 27-43, wherein the valve isconfigured to be placed in-line between a patient interface and ablower.

45. The valve of any one of paragraphs 27-44, wherein the at least oneinternal member is attached to the body by posts that extend through thebody.

46. The valve of any one of paragraphs 27-44, wherein the at least oneinternal member is attached to the body by an adhesive.

47. The valve of any one of paragraphs 27-44, wherein the at least oneinternal member is attached by overmoulding onto the body.

48. The valve of any one of paragraphs 27-47, wherein the valve is ananti-asphyxia valve.

49. The valve of any one of paragraphs 27-47, wherein the valve is aconstant flow valve.

50. The valve of paragraph 49, wherein the at least one internal membertransitions between the open configuration and the closed configurationduring pressures ranging from at least approximately 0 cm H2O and/orless than or equal to approximately 20 cm H2O.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to.”

Where, in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers areherein incorporated as if individually set forth.

The invention may also be said broadly to consist in the parts, elementsand features referred to or indicated in the specification of theapplication, individually or collectively, in any or all combinations oftwo or more of said parts, elements or features.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that thatprior art forms part of the common general knowledge in the field ofendeavour in any country in the world.

Certain features, aspects and advantages of an embodiment of the presentinvention have been described with reference to a CPAP apparatus,particularly for use in the treatment of obstructive sleep apnea.However, certain features, aspects and advantages of the valve asdescribed above may be advantageously used with other therapeutic ornon-therapeutic breathing devices, such as non-invasive ventilators, orfor the treatment of other conditions, such as COPD. Certain features,aspects and advantages of the method and apparatus of the presentdisclosure may be equally applied to other breathing devices for otherconditions.

Although the present inventions have been described in terms of certainembodiments or configurations, other embodiments apparent to those ofordinary skill in the art also are within the scope of these inventions.Thus, various changes and modifications may be made without departingfrom the spirit and scope of the inventions. For instance, variouscomponents may be repositioned as desired. Moreover, not all of thefeatures, aspects and advantages are necessarily required to practicethe present inventions. Accordingly, the scope of the present inventionsis intended to be defined only by the claims that follow.

What is claimed is:
 1. A valve configured for use in positive airwaypressure therapy, the valve comprising: a tubular body with an interiorsurface and an exterior surface, the interior surface surrounding apassageway through which fluids can flow; one or more ports comprisingthrough holes in the tubular body that extend from the interior surfaceto the exterior surface such that the passageway is in fluidcommunication with an environment through the one or more ports; atleast one internal member attached to the tubular body at two or morediscontinuous attachment positions on the at least one internal member;wherein the at least one internal member comprises an elongate ribbonthat is opposed to the one or more ports of the valve, the at least oneinternal member having an open configuration in which the elongateribbon curves away from the interior surface of the tubular body and aclosed configuration in which the elongate ribbon abuts the interiorsurface to occlude the one or more ports; and wherein the two or morediscontinuous attachment positions are evenly spaced around acircumference of the at least one internal member.
 2. The valve of claim1, wherein the interior surface is curved.
 3. The valve of claim 1,wherein the interior surface is curved, and wherein the elongate ribboncurves with the interior surface in the closed configuration of the atleast one internal member.
 4. The valve of claim 1, wherein the at leastone internal member is configured to progressively roll over theinterior surface of the tubular body.
 5. The valve of claim 1, whereinthe at least one internal member transitions between the openconfiguration and the closed configuration at a distinct thresholdpressure within the tubular body.
 6. The valve of claim 1, wherein theone or more ports are circular holes having a diameter of approximately1 mm.
 7. The valve of claim 1, wherein the one or more ports have acombined venting area of at least approximately 30 mm² and/or less thanor equal to approximately 600 mm².
 8. The valve of claim 1, wherein athreshold pressure within the tubular body is approximately 2 cm H₂O. 9.The valve of claim 1, wherein a length of the at least one internalmember between attachment positions is approximately the same as alength of the interior surface of the tubular body between theattachment positions.
 10. The valve of claim 1, wherein the at least oneinternal member is a continuous member configured to extend around theinterior surface of the tubular body in the closed configuration. 11.The valve of claim 1, wherein the valve is configured to be placed at aninlet of a patient interface.
 12. The valve of claim 1, wherein thevalve is configured to be placed in-line between a patient interface anda blower.
 13. The valve of claim 1, wherein the at least one internalmember is attached to the tubular body by posts that extend through thetubular body.
 14. The valve of claim 1, wherein the at least oneinternal member is attached to the tubular body by an adhesive or byovermoulding onto the tubular body.
 15. The valve of claim 1, whereinthe valve is a constant flow valve.
 16. The valve of claim 1, whereinthe at least one internal member is configured to be in the openconfiguration when gas flow pressure in the valve is below a thresholdpressure within the tubular body.
 17. The valve of claim 1, whereinfluids can flow from a first end of the tubular body to a second end ofthe tubular body when the at least one internal member is in the openconfiguration and when the at least one internal member is in the closedconfiguration.
 18. The valve of claim 1, wherein the at least oneinternal member transitions between the open configuration and theclosed configuration during a range of pressures within the tubularbody.
 19. The valve of claim 18, wherein the range of pressures is atleast approximately 1.5 cm H₂O and/or less than or equal toapproximately 4 cm H₂O.
 20. A valve configured for use in positiveairway pressure therapy, the valve comprising: a tubular body with aninterior surface and an exterior surface, the interior surfacesurrounding a passageway through which fluids can flow; one or moreports comprising through holes in the tubular body that extend from theinterior surface to the exterior surface such that the passageway is influid communication with an environment through the one or more ports;at least one internal member attached to the tubular body at two or morediscontinuous attachment positions on the at least one internal member;wherein the at least one internal member comprises an elongate ribbonthat is opposed to the one or more ports of the valve, the at least oneinternal member having an open configuration in which the elongateribbon curves away from the interior surface of the tubular body and aclosed configuration in which the elongate ribbon abuts the interiorsurface to occlude the one or more ports; wherein movement of theelongate ribbon is in a direction perpendicular to a flow of air throughthe tubular body; and wherein the two or more discontinuous attachmentpositions are evenly spaced around a circumference of the at least oneinternal member.